Camera modules include an imaging integrated circuit (chip) packaged with optics. These camera modules are useful for manufacturers of consumer devices, such as cellular telephone manufacturers that want to integrate a camera into their cellular telephones. The Agilent CMOS ADCM-2650-0001 Camera Module product is an example of a camera module that is available from the assignee of the current patent application.
The camera module generates output images at a rate determined by the internal circuits of the module (e.g., the imager chip). Other components that use the output images generated by the camera must accept the output images at the rate set by the camera module. In other words, the camera module (e.g., the imager chip) sets the rate at which the other components must process or store the output images. Otherwise, information is lost. For many applications, such as video applications, the other components that interface to the camera module must employ expensive frame memories or digital signal processors to accommodate the rate at which the camera module generates the output images. This undesirably increases the cost of such components and at the same time limits certain types of image processing and requires the use of expensive DSP integrated circuits and memories. In other words, it is difficult if not impossible for less powerful processors or components with limited memory to use output images generated by the camera module, thereby increasing the difficulty of integrating such components with the camera module.
Moreover, existing cameras produce images of fixed resolution. For example, VGA has a resolution of 480×640 pixels. Some cameras have a feature where a user can select a region of interest that is smaller than the field of view and apply a digital zoom feature.
Other cameras have a feature where images of reduced resolution image can be generated by sub-sampling for display on a small screen (e.g., a display on a cellular telephone). For example, the camera module noted previously includes a sizer that performs sub-sampling on a sensor image to generate an output image for display on a small screen, for example. However, when sub-sampling light information is lost and may lead to undesirable image artifacts. Also, the bit depth in prior art cameras is not adjustable.
In a system that performs image processing with limited computational resources, these prior art cameras are a severe disadvantage. In such systems, it is important to reduce energy consumption and to save processing time. In order to achieve these goals, it is important to provide an image to a computing resource with the minimum resolution necessary to achieve the desired image processing result.
Based on the foregoing, there remains a need for a camera that can generate output images with configurable resolution and that overcomes the disadvantages set forth previously.